#include <stdio.h>

struct complex
{
    int real;
    int imag;
};

struct complex multiply(struct complex x, struct complex y);

int main()
{
    struct complex product, x, y;

    scanf("%d%d%d%d", &x.real, &x.imag, &y.real, &y.imag);
    product = multiply(x, y);
    printf("(%d+%di) * (%d+%di) = %d + %di\n",
           x.real, x.imag, y.real, y.imag, product.real, product.imag);

    return 0;
}

/* 你的代码将被嵌在这里 */
struct complex multiply(struct complex x, struct complex y)
{
    struct complex aa;
    aa.real = (x.real * y.real) - (x.imag * y.imag);
    aa.imag = (x.real * y.imag) + (x.imag * y.real);
    return aa;
};
